hollingsworth



1956 A. v. HOLLINGSWORTH 2,733,550

GRAVITY ABRASION APPARATUS Filed Jan; 5, 1953 2 Sheets-Sheet 1 INVEN TOR. HAP/e50 lfflazu/vwwm'rv.

Feb. 7, 1956 A. v. HOLLINGSWORTH 3 GRAVITY ABRASION APPARATUs Filed Jan. 5, 1955 2 Sheets-Sheet 2 United States Patent- O G AV Y A RA Q EARATUS- Alfred V. Hollingsworth, Indianapolis, Ind. Application January 5, 1953, Serial No. 329,662; 4 Claims. (Cl. 51 .-15;)

T s n ent on r lates g n ra y o dehurting n p lshi s appar tu a d nore'p u ar y i e a es, to apparatus for dropping abrasive materials by gravity into contact; with workpieces for polishing or d eburring.

It is conventional to abrade workpieces by tumbling them in a mass with one another or; by tumbling them in a mass of abrasive material such as granite chips, shot 7 he. like. It is also conventional to forcibly discharge abrasive materials such as shot or granite; chips into contact with a work piece. Conventional; methods and apparatus. such as those outlined above, remove; a sub stantial amount of material from the work; piece whereby i s phy i m io r teri l y ch ng dan the surfaces are pitted or roughened to s l h a. degree as to require a finishing; or polishing operation. In other; words, conventional methods and apparatus; are not dap d t p o m a fi g ope on. whereby many types of; manufacturing operati ns; a work piece must be deburred by hand filing or grinding and/or a final polishing operation must be use d for obtaining a finh d su fa Accordingly, it is theprincipal object ofthis invention to Provide apparatus adapted to apply bulk abrasive materials to a work piece for polishing it or deburring it.

Another object of this invention is to provide apparatus adapted to polish and deburr work pieces as a final operation. by applying abrasive in bulk under the influence of gravity.

Still another object of this invention is to provide apparatus for polishing or deburring a work piece which is capable of performing the deburring or polishing operation without materially changing the, dimensions of the work piece.

In accordance with this invention there is provided polishing and deburring apparatus comprising an abrasive carrying mechanism adapted to drop a stream of bulk abrasive material, and a rotatable table for supporting work pieces and moving them into the path of the stream of abrasive materials.

The full nature of the invention will be understood from the accompanying drawings and the following de scription and claims:

Fig. l is a front elevation view, with parts broken away, of the polishing and deburring apparatus provided in accordance with this invention.

Fig. 2 is a side elevation view, partially in crosssection, of the apparatus illustrated in Fig. 1.

Fig. 3 is an enlarged perspective view of the buckets illustrated in Fig. 1.

Referring to the drawings, there is provided in accordance with this invention a gravity abrading device comprising a drum rotatably supported on a shaft 11 mounted in suitable bearings 12 on a stand 14. Shaft 11 may be driven from a motor (not shown) through a chain drive 15 or other suitable drive mechanism.

Drum 10 comprises a back wall 17 in the form of a disc which may be supported on shaft 11 by means of a, plate 18 having a hub 19 fixed to the end of shaft 11. The periphery of drum 10. is closed by a cylindrical wall 20; and the front of drum 10 comprises an annular flange portion 21 formed to provide an annular opening 23, whereby thereis access to the interior of the drum. For elevating abrasive materials from the lower portion of the drum to the upper portion thereof as the drum rotates, there are provided a plurality of spaced buckets 24 adjustably pivoted 0n bolts 25 mounted in the outer periphery of .the drum. Buckets 24 may beadju sted about the bolts 25. and clamped in the desired position by-"means of a ring member 27 slidably mounted on: the back member 17 of the drum. by means of bolts 28', which project through slots 29 in ring 27. Each of the buckets 24 may be pivotally connected to band 27 by the pin 30, whereby as ring 27 is rotated with respect to member 17, the angle of buckets 24 may be adjusted. Wing nut 31 on bolt 28 may be tightened to maintain adjustment of the buckets.

Various types of abrasive materials such as granite chips, shot, earth, ground corn cobs in combination with water may. be loaded into drum 10 whereby, as the drum rotates, each of the buckets 24 carries a quantity'of abrasive material in water upwardly to a desired point where the abrasive material slides off the buckets and drops. This point of discharge of abrasive materials from buckets 24 and the angle at which the abrasive impacts a work piece may bedetermined by adjusting the angular relationship of the buckets to the periphery ofthe drum. Various abrasives in soluble oil' mixtures may alsobe used in this device.

For supporting work pieces in the path of dropping abrasive material, there is provided a rotatable table 32 mounted. on a vertical shaft 33 which is in turn rotatably supported on a movable dolly 34, whereby table 32 may be loaded with work pieces and moved into the position illustrated in Fig. 2 where approximately onehalf of the table is within drum 10 for moving one work piece after another through the stream of falling abrasive material. The table 32 and shaft 33 may be connected to. a drive motor 36. through a suitable gear reduction. mechanism. 37', whereby table 32 may be rotated. at a; predetermined speed to expose each work piece to. a predetermined amount of abrasive material: Table 32' may comprise a bottom. portion of meshed wire screening 39 secured toa centrally located plate 40 and supportingan annular peripheral wall member 41. At the outer extremity of table 32 there may be provided a shield 42 adapted to protect a workman from the moving table 32. If desired, shield 42 may be considerably higher with. respect to table 32 than, illustrated in the drawings in order to. protect the operator from spattering abrasive material. l

In operation the drum 10 rotates at a predetermined speed and may contain a predetermined amount of abrasive material in the water, whereby each of the buckets 24 discharges a certain amount of abrasive material. Work pieces may be placed on table 32 as it rotates and moved one after the other through the stream of abrasive material whereby burrs may be removed from the work piece and its surfaces polished. Table 32 may be continuously loaded and unloaded after each work piece has ben exposed to one treatment with abrasive material, or if the particular polishing operation requires a certain number of passes through the absasive material, table 32 may be loaded and allowed to move the work pieces through the stream of abrasive material a predetermined number of times. After such treatment the table may be unloaded and then reloaded with a new batch of work pieces.

The gravity abrasion device provided by this inven- :chines.

tionis especially adapted for polishing and deburring otherwise finished work pieces due to the fact that the abrasive material has only that velocity which is imparted by the influence 'of gravity, this beinga relatively low velocity compared with conventional abrading ma- ,Becaus'e of the choice of abrasive materials which is available and because of the low velocity of the materials, a work piece may be polished removing an infinitesimal amount of material from the work piece whereby its finished dimensions are not changed to any material degree, and remain within the prescribed tolerances after the polishing operation is completed.

This invention is especially adapted to polish items such as turbine blades or buckets for jet engines, as it is imperative that no transverse polish marks be left on turbine blades. Such polish marks cause fracture of the blades and destruction of the jet engine. With the abrading device provided by this invention blades can be mounted on table 32 or within drum so that the action of the abrasive material will leave longitudinal polish marks which are harmless and have no effect on structural strength of the blades.

It it 'is desired to polish cylindrical items such as tops for Thermos bottles, rotating work holders may be mounted on table 32 thereby to expose all of the cylindrical surface to polishing action of the abrasive. Polishing of such items has heretofore been impractical or impossible in conventional abrading machines.

Because of the low velocity of the abrasive materials, as provided herein, softer metals may be polished without injury. Heretofore it has been impossible to polish such materials in machines of the general type disclosed herein because the relatively high velocity of the abrasive material will destroy items comprising soft metals.

A further advantage of this invention is the uniformity of deburring, for example. According to conventional practice it has been customary to deburr by means of manually filing the corners of wood pieces having intricately arranged interior surfaces. Filing by hand is not productive of uniformity, whereas deburring by means of this invention produces uniform removal of metal whereby every work piece is identical when finished.

The invention claimed is:

1. A polishing and deburring apparatus comprising a drum having a rotatable supporting means for rotating it about a horizontal axis, buckets pivotally mounted inwardly of the periphery of said drum, means operatively associated with said drum and said buckets for adjusting the angular relation of said buckets to said drum for dropping abrasive materials at a predetermined point in the path of rotation of said drum to establish a stream of free-falling materials, one side of said drum including a ring member defining an abrasive carrying space within said drum and providing access to the interior of said drum,,and a horizontal table mounted adjacent to the open side of and extending within said drum for rotation 4 in the stream of abrasive materials falling from said buckets, said table comprising a screen adapted to support work pieces and permit passage therethrough of abrasive materials.

2. A polishing and deburring apparatus comprising a drum having a rotatable supporting means for rotating it about a horizontal axis, buckets mounted inwardly of the periphery of said drum for dropping abrasive materials at a predetermined point in the path of rotation of said drum to establish a stream of free-falling materials, one side of said drum being open and including a ring member defining an abrasive carrying space within said drum and providing access to the interior of said drum, and a horizontal table mounted adjacent to the open side of and extending partially within and partially without said drum for rotation of a portion of said table in the stream of abrasive materials falling from said buckets, said table comprising a screen adapted to support work pieces and permit passage therethrough of abrasive materials.

3. A polishing and deburring apparatus comprising a drum having a rotatable supporting means for rotating it about a horizontal axis, buckets mounted inwardly of the periphery of said drum for dropping abrasive materials at a predetermined point in the path of rotation of said drum to establish a stream of free-falling materials, one side of said drum being open and including a ring member defining an abrasive carrying space within said drum and providing access to the interior of said drum, and a horizontal table mounted adjacent to the open side of'and extending partially within and partially without said drum to position a portion of said table in the stream of abrasive materials'falling from said buckets, said table comprising a means adapted to support work pieces and permit passage of abrasive materials to the lower side of said drum.

4. A polishing and deburring apparatus comprising an open-sided drum rotatable about a horizontal axis, abrasive conveying means adjacent the periphery of said drum for dropping abrasive material through a well defined free-falling path, and a horizontal table mounted adjacent to and extending partially within and partially without the open side of said drum for rotation into and out of the path of free-falling abrasive materials falling from said conveying means.

References Cited in the file of this patent UNITED STATES PATENTS 497,714 Eshleman May 16, 1893 573,180 Gutmann Dec. 15,.1896 2,224,545 Lach Dec. 10, 1940 2,429,742 Barnes Oct. 28, 1947 2,478,156 Gladfelter Aug. 2, 1949 2,665,118 Broman Jan. 5, 1954 

